Trouble with Nipples

I'm having a bit of trouble getting my nipple situation sorted out for the spout of my tub shower combo.

I've measured from the front face of the wing back 90 in the wall and came up with 2-11/16". Now I assume that 1/2" of nipple should go into the wing back 90. The spout I have is a Kohler and the specs say to have 7/16" of nipple sticking out of the wall. Add all this up and I get 3-5/8".

I can only seem to find brass nipple lenghts that are even number of inches (2, 3, 4, 5 etc...). I found one that has one end threaded for the wing back 90 then a couple inches unthreaded then 3 or so inches threaded which I assumed could be cut to the appropriate length. Well, I tried screwing the long end that I thought should be cut into either the wing back 90 or the spout I have and I only make it in like 1 or 2 threads. Apparently the fittings have tapered threads and this pipe isn't tapered? Is that the problem?

So, if it is, how would I go about solving this problem I'm having? There must be something I'm missing.

I found a 3.5" nipple but it's black steel which I assume isn't good for water. Am I right about that? Also don't want rust in the tub.

If I can find a 3.5" brass nipple, could I use that and just apply more teflon tape or something to the pipe and not screw it in as far?

There must be a simple solution.

Any help would be greatly appreciated.

Dan

Attached Files:

Any of the Plumbing shops in town should have a 3-1/2" brass or galvanized nipple. You might want to figure a little less than 1/2" going into the threads. You don't want to over-tighten that brass fitting in the wall. Usually around 3/8" is good with brass.

If you're determined to shop in the orange box, pick up a 5" brass nipple and have them cut and thread to your exact spec. Forget galv.

Click to expand...

Good luck with that. Around here, most of the stores do have a nipple jig for their threader. Good luck (a) there might be one guy in the plumbing section who even knows where it is (b) he has probably never used it.